From owner-freebsd-current@FreeBSD.ORG Tue Feb 24 14:12:02 2004 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 2DBEA16A4CE; Tue, 24 Feb 2004 14:12:02 -0800 (PST) Received: from freebee.digiware.nl (dsl390.iae.nl [212.61.63.138]) by mx1.FreeBSD.org (Postfix) with ESMTP id 33E4943D2D; Tue, 24 Feb 2004 14:12:01 -0800 (PST) (envelope-from wjw@withagen.nl) Received: from dual (dual [212.61.27.71]) by freebee.digiware.nl (8.12.10/8.12.9) with SMTP id i1OMAWeL058708; Tue, 24 Feb 2004 23:10:32 +0100 (CET) (envelope-from wjw@withagen.nl) Message-ID: <084901c3fb23$0ec737f0$471b3dd4@dual> From: "Willem Jan Withagen" To: "Robert Watson" References: Date: Tue, 24 Feb 2004 23:10:47 +0100 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1158 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 cc: freebsd-performance@FreeBSD.ORG cc: current@FreeBSD.ORG Subject: Re: The effects of WITNESS and INVARIANTS X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 24 Feb 2004 22:12:02 -0000 From: "Robert Watson" > On Tue, 24 Feb 2004, Willem Jan Withagen wrote: > > > Just out of curriousity, and 'cause I've got some idle boxes, I started > > to do some (NFS-)performance testing. There is still a long way to go, > > but I've but a first obvious result online running on the local server > > disk. > > > > It makes the claims of the effects of WITNESS and INVARIANTS very > > obvious. Look especially at the graph for "Sequential block read". > > > > You might want to have a look at: > > http://withagen.dyndns.org/FreeBSD/nfs-performance/index.html. Note > > that no NFS data is included. I have some Bonnie-NFS data, but need to > > write accompanying test and conclusions for it. > > > > Suggestions are more than welcomed. > > My primary suggestion is "Turn off WITNESS and INVARIANTS when > benchmarking or for production systems". We turn them off in releases, > and once 5.x becomes 5-stable, we'll turn it off by default also. However, > they're invaluable tools when debugging the development system, so we have > them on in the development branch by default. I would encourage people to > generally run with them turned on unless performance of a system requires > them to be off, as it really helps the debugging process, as well as > helping to identify locking problems as the system evolves. Hi Robert, I understand your concern and will take your remark as made here, and put it in the document as a "Nota Bene"... And I'll emphasise the fact that the 5-stable fact is the turning corner for this matter. --WjW